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United States Patent | 5,037,491 |
Fox | * August 6, 1991 |
A method for improving the wear characteristics and corrosion resistance of a metal surface having the basic steps of: A. case hardening the metal surface by placing the metal in a fluidized bed and exposing it to a first atmosphere of nitrogen, ammonia and natural gas at a temperature between about 750.degree. F. and about 1200.degree. F. for a period between about 1 and about 5 hours, followed by exposure to a second atmosphere containing nitrogen and water at a temperature between about 750.degree. F. and about 1200.degree. F.; B. coating the metal with an aqueous coating composition consisting essentially of a polymeric additive and water; and C. allowing the coating composition retained on the metal to cure for a period between about 2 and about 48 hours.
Inventors: | Fox; Patrick L. (1684 Graefield, Birmingham, MI 48008) |
[*] Notice: | The portion of the term of this patent subsequent to July 12, 2005 has been disclaimed. |
Appl. No.: | 207327 |
Filed: | June 15, 1988 |
Current U.S. Class: | 148/209; 148/217; 148/218; 148/318; 148/319 |
Intern'l Class: | C21D 001/74 |
Field of Search: | 148/16,16.5,16.6,203,318,319,316,317 |
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______________________________________ DOW DOW CORNING CORNING 531 536 ______________________________________ Active Ingredients(%) 50 100 Solvents Aliphatic Solvents none & Isopropyl alcohol Viscosity @ 77.degree. F.;(cs) 150 35 Refractive Index @ 77.degree. F. 1.410 1.408 Specific Gravity 0.860 0.985 Flash Point, closed cup 56 60 Pensky-Martin Method (.degree.F.) ______________________________________